How to unlock lumia 640?

I bought a lumia 640 and after i factory reset it, the phone asks me to provide a security code. The previous owner of the phone claims to have forgotten the code hence i can not use the phone. I need a way to solve this issue.

You cant. The device has reset protection. The previous owner may be able to go to account.microsoft.com and under devices find the recovery code or disable reset protection but that may or may not still be there.

You cant. The device has reset protection. The previous owner may be able to go to account.microsoft.com and under devices find the recovery code or disable reset protection but that may or may not still be there.